Jesus was the physical manifestation of what was true in the Spirit realm.  God is Spirit (John 4:24) and is in the spiritual realm, but then Jesus Christ became the manifestation that was brought into the physical realm.  This is a main proof that what is true in the spiritual realm can be pulled into this physical realm (by faith).  I imagine the demons in shock at seeing Jesus and asking themselves, “what is He doing here in this world?!”  They recognized that Jesus had the fullness of God in Him (Mark 1:24, Matthew 8:29) and that He Himself knew that (John 13:3, Colossians 2:9).  The spirits of darkness also experienced firsthand the power of Jesus’s Name, especially when being commanded and having to leave people by His words and authority.
The enemies of darkness still do know who the Lord Jesus is and, since I have The Lord in me like Jesus had God fully in Him (1John 4:17), the darkness knows who I am…the full effectiveness, though, comes in me knowing and acknowledging this in myself (Philemon 1:6) and the power of the Name I’ve been given privilege to use. 
In Acts 19:13-15, a demon was confronted by seven brothers who were trying to use the identity of the apostle Paul. The demon responded to the brothers with “I know Jesus and I’ve heard of Paul, but who are you?” (Acts 19:15).  The enemy acknowledged and recognized those who had the Lord in them and who knew who they were in Him.  The brothers, on the other hand, did not have and know that precious identity and were defeated, not even being recognized by the enemy.
So seek a true revelation of the fact that, if you are one who has recieved salvation, you truly are a ‘temple of the living God’ (1Corinthians 3:16) which means privilege, power, victory and closeness with the Holy Trinity…to name a few wonderful benefits! You have authority and also the privilege of using the powerful name of Jesus to live the abundant life the Lord has provided you!